SST provides both by-value and by-reference marshaling capabilities using the Swapper. Both techniques are implemented by the class SstSwapperMarshaler which coordinates instances of the Swapper's ObjectLoader and ObjectDumper. The behavior of these objects is controlled by strategies which are programmable.

SST by-value marshaling is implemented as a simple, thin wrapper on the Swapper. By-reference marshaling is implemented using more detailed variations of the swapping strategies.

Advanced users may be interested to know that by-value marshalers use the standard ObjectLoader and ObjectDumper with no special replacers. You can use the normal the Swapper API to affect the way particular objects, classes and instance variables are marshaled. This is independent of the marshaling framework. The same is true of the by-reference marshaler but more care must be taken in changing the behavior of the replacers and loaders/dumpers. For more detailed information on the Swapper, refer to the Smalltalk User Guide.